In this paper a proposal has been made for the radiator to be used for the measurements and numerical simulations of test case d: 'free convection with radiator'. The selection of the radiator is based on the identical testroom configuration as described in 'R.I. 1.3 : Test room, identical testrooms'. Thisconfiguration consists of a window with single glazing. However data for double glazing is also presented. A radiator of a well known manufacturer has been chosen, in order to make sure that the radiator is available in each participating country. Another possibility is to use one radiator and send it to each participant after the measurements.